MAGE-A4-Specific TCR Engineering for Potent, Selective Tumor Targeting
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Solution Overview
Problem
Current TCR-T cell therapies face challenges in recognizing tumor-specific antigens due to the rarity of tumor-specific T cells, difficulty in expanding them ex vivo, and potential exhaustion or suppression, leading to issues like autoimmunity and limited therapeutic efficacy.
Innovation Solution
Identification of TCR sequences specific to MAGEA4 peptide-MHC complexes, such as KVLEHVVRV/HLA-A*02:01 and GVYDGREHTV/HLA-A*02:01, and engineering TCR-T cells with an activation-dependent IL12 payload to enhance in vivo efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TCR affinity is enhanced to increase sensitivity to tumor antigens, then therapeutic potency is improved, but cross-reactivity to self-antigens increases causing autoimmunity
Solution Approach 1:
The patent modifies TCR parameters by engineering chimeric TCRs with altered CDR regions to achieve optimal affinity for tumor antigens while maintaining selectivity. Specific amino acid substitutions in CDR3 regions adjust binding parameters to recognize tumor-specific pMHC complexes with high affinity without cross-reacting with self-antigens like titin
Solution Approach 2:
The patent applies local quality by making specific modifications to the CDR regions of TCR while keeping framework regions intact. The CDR3 alpha and CDR3 beta regions are specifically engineered to recognize tumor antigens with high affinity, while other regions maintain normal TCR structure to avoid off-target binding
2Strength
If TCR-T cells are engineered with higher affinity for tumor antigens, then cytotoxicity against tumor cells is improved, but toxicity to normal tissues increases
Solution Approach 1:
The patent carefully adjusts TCR affinity parameters through rational design of CDR regions, achieving optimal binding strength for tumor antigens while avoiding excessive affinity that would cause off-target toxicity. The affinity is tuned to be sufficiently high for effective tumor cell killing but selective enough to spare normal tissues
Solution Approach 2:
The patent replaces natural TCRs with engineered chimeric TCRs that have modified recognition properties. These engineered TCRs substitute the natural binding mechanism with a redesigned interface that specifically recognizes tumor antigens while ignoring self-antigens, thereby reducing off-target toxicity
3Quantity of substance
If tumor-specific T cells are expanded ex vivo, then therapeutic dose is improved, but cell exhaustion or suppression occurs
Solution Approach 1:
The patent performs preliminary action by pre-engineering TCRs with optimal affinity and specificity before expansion. The TCR-T cells are transduced with engineered TCR constructs that confer high potency, allowing for effective therapy at lower cell doses and reducing the need for extensive ex vivo expansion that would cause exhaustion
Data Source
AI summary
Provided herein are recombinant T-cell receptors (TCRs) that can selectively recognize the MAGE-A4-derived peptide GVYDGEEHSV or KVEEHVVRV when presented by HLA-A*0201 sufficiently to activate the recombinant T cell. TCRs provided herein were thoroughly screened for lack of cross-reactivity with similar peptides that may be presented by normal cells or tissue and for alloreactivity.